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H Zhou

Publications and source records attributed to H Zhou.

At least 487 records · Page 27Linked to original sources
PubMed1997

Role of m1 receptor-G protein coupling in cell proliferation in the prostate.

The prostate gland from several animal species contains variable levels of muscarinic subtypes, but only the human prostate expresses significant levels of the m1 subtype. We studied muscarinic receptor activity in human benign prostatic hypertrophy (BPH) as well as several cell lines derived from prostate cancer. The BPH we studied expresses approximately 75% of the m1 receptor and undetectable levels of the other receptor subtypes whereas PC3 cells express only the m3 receptor subtype. DU145 and LnCaP cells express approximately equal levels of m1 and m3 receptor subtypes. Only the PC3 cells responded to carbachol with an increase in turnover of polyphosphoinositides, and none of the cell lines responded with effects on cAMP metabolism. Co-precipitation of receptors with heterotrimeric guanine nucleotide-binding regulatory proteins demonstrated interactions of the m1 receptors with Gi, Gq and G16 in BPH tissue and of the m1 and m3 receptors with Gi, Gq and G12 in PC3 and DU145 cells. Mitogen activated protein kinase (ERK) activity was seen in response to carbachol in PC3 and DU145 but not LnCaP cells. Finally, carbachol promoted cell proliferation in all three cell lines. Thus, there appears to be no consistent relationship between ERK activity, cell proliferation, and the subtype mediating the proliferative response, amongst these prostate cancer cell lines.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

The winged helix transcriptional activator HFH-8 is expressed in the mesoderm of the primitive streak stage of mouse embryos and its cellular derivatives.

The hepatocyte nuclear factor 3/fork head homolog (HFH) proteins are an extensive family of transcription factors which share homology in the winged helix DNA binding domain. Members of the winged helix family have been implicated in cell fate determination during pattern formation, in organogenesis and in cell type-specific gene expression. In this study, we used in situ hybridization to identify the cellular expression pattern of the winged helix transcription factor, HFH-8, during mouse embryonic development. We showed that HFH-8 expression initiates during the primitive streak stage of mouse embryogenesis in the extraembryonic mesoderm and in the lateral mesoderm which gives rise to the somatopleuric and splanchnopleuric mesoderm. During organogenesis, HFH-8 expression is found in the splanchnic mesoderm in close apposition of the gut endoderm, suggesting a role in mesenchymal-epithelial induction of lung and gut morphogenesis. HFH-8 expression continues in lateral mesoderm-derived tissue throughout mouse development. HFH-8 expression is observed in the mesenchymal cells of the oral cavity, esophagus, trachea, lung, intestine, dorsal aorta and intersomitic arteries, but not in the vasculature of the head, liver, kidney or heart. Consistent with these embryonic expression studies, adult HFH-8 expression is restricted to the endothelium and connective fibroblasts of the alveolar sac and in the lamina propria and smooth muscle of the intestine. We also show that several adult endothelial cell lines maintain abundant HFH-8 expression. Furthermore, we used our determined HFH-8 consensus sequence to identify putative target genes expressed in pulmonary and intestinal mesenchymal cells. Cotransfection assays with one of these target promoters, P-selectin, demonstrated that HFH-8 expression was required for IL-6 stimulation of P-selectin promoter activity and suggest that HFH-8 is involved in mediating its cell-specific transcriptional activation in response to cytokines.

Animals↗
PubMed1997

Temporal expression of PTHrP during endochondral bone formation in mouse and intramembranous bone formation in an in vivo rabbit model.

Expression of parathyroid hormone-related protein (PTHrP) messenger RNA (mRNA) and protein was investigated throughout the developmental progression of endochondral bone formation in mouse and intramembranous bone formation in an in vivo model in rabbit, using in situ hybridization and immunohistochemistry. Endochondral bone formation was investigated in a developing embryo, newborn, and adult mouse. In fetal long bones through to newborn (day 7), PTHrP mRNA and protein were consistently expressed in chondrocytes within the proliferative, transitional, and hypertrophic zones. In addition, high levels of PTHrP were also detected in osteoblasts on the surface of trabecular bone surfaces. Similarly, at the adult stage (week 7), PTHrP mRNA and protein were consistently expressed in chondrocytes at epiphyseal ends of the subarticular cartilage, within cortical periosteum, as well as in osteoblasts located at the metaphyseal trabecular bone surfaces. Using an in vivo intramembranous bone formation model in rabbits, expression of PTHrP mRNA and protein was demonstrated in preosteoblasts prior to trabecular bone formation (1-week bone harvest). As bone formed (2-, 3-, and 4-week bone tissue harvests), PTHrP mRNA and protein were highly expressed in actively synthesizing osteoblasts and in those osteocytes embedded within the superficial layers of the bone matrix. Lining osteoblasts and osteocytes buried deeply in the bone matrix displayed weak or no signal for PTHrP. The pattern of spatial and temporal expression of PTHrP demonstrated in cartilage cells and osteoblasts in the two systems suggests an important role of PTHrP in both endochondral and intramembranous bone formation.

Animals↗
PubMed1997

Context sequences of translation initiation codon in plants.

In this survey of 5074 plant genes for their AUG context sequences, purines are present at the -3 and +4 positions in about 80% of the sequences. Although this observation is similar to the vertebrate consensus sequence, the number of plant mRNAs with purines at the -3 position is lower and at the +4 position is higher than reported for vertebrate mRNAs. Higher plants have an AC-rich consensus sequence. caA(A/C)aAUGGCg as a context of translation initiator codon. Between the two major groups of angiosperms, the context of the AUG codon in dicot mRNAs is aaA(A/C)aAUGGCu which is similar to the higher-plant consensus but monocot mRNAs have c(a/c)(A/G)(A/C)cAUGGCG as a consensus which exhibits an overall similarity with the vertebrate consensus. The experimental evidence regarding the importance of the AUG context in plants is discussed.

Codon↗
PubMed1997

The impact of the quantity of skeletal injury on mortality and pulmonary morbidity.

OBJECTIVE: To determine if the quantity of skeletal injuries (and the timing to fixation) increases the mortality or pulmonary morbidity in patients with and without chest injuries. DESIGN: Retrospective analysis of trauma registry. Statistical analysis with multiple logistic regression and chi(2) analysis. METHODS: Looking specifically at adult patients (> 16 years), skeletal injury was quantified by determining the presence or absence of a fracture in specific body regions (humeri, forearm, femur, tibia, spine, and pelvis) for a maximum of 10 skeletal injuries. The timing of fixation for fractures was categorized as < 24 hours, < 48 hours, < 72 hours, < 5 days, > 5 days, or no fixation. Chest injuries and pulmonary morbidity were based on the accepted list of complications reported in the literature. RESULTS: Three groups were analyzed according to the presence or absence of a chest or skeletal injury: those without skeletal injury (group NSI, n = 59), those without chest injuries (group NCI, n = 108), and those with both skeletal and chest injuries (group B, n = 59) Pulmonary Complications: When all patient groups (NCI, NSI, and B) were pooled, greater chest injury (p < 0.0008), greater skeletal injury (p < 0.02), and delayed fixation (p < 0.04) were associated with increased risk of developing a pulmonary complication. In the group of patients without a chest injury (NCI), this risk was associated with greater head injury (p < 0.005) and greater skeletal injury (p < 0.04), whereas in the group without a skeletal injury (NSI), only chest injury demonstrated significance (p < 0.05). When both skeletal and chest injuries were present, greater head injury (p < 0.03) and fixation time (p < 0.03) increased the risk of developing a pulmonary complication. Mortality: With all patients pooled (NCI, B, and NSI), head injury (p < 0.02), abdominal injury (p < 0.012), and fixation time (p < 0.01) were risk factors. In patients without a chest injury (NCI), none of the indexed variables were associated with mortality. In patients without a skeletal injury (NSI), greater head injury (p < 0.01), greater chest injury (p < 0.01), and greater abdominal injury (p < 0.04) were risk factors for mortality. When both chest and skeletal injuries were present (B), only head injury (p < 0.0003) was associated with mortality. The prevalence of mortality and pulmonary complications were compared between groups NCI, NSI, and B. Group NCI had fewer pulmonary complications (p < 0.004) than the other groups (difference not significant). When examining mortality, group NCI had less mortality than groups NSI and B. CONCLUSION: The combination of skeletal and chest injuries does not seem to amplify the pulmonary morbidity and mortality compared with chest injury alone. The quantity of the skeletal injury and the time to fixation of structures affecting mobilization seem to have an effect on pulmonary morbidity and mortality. Better scientific studies on the effects of skeletal injury and timing to fixation in relation to pulmonary morbidity and mortality are required.

Adult↗
PubMed1997

Categorical regression analysis of acute exposure to tetrachloroethylene.

Exposure-response analysis of acute noncancer risks should consider both concentration (C) and duration (T) of exposure, as well as severity of response. Stratified categorical regression is a form of meta-analysis that addresses these needs by combining studies and analyzing response data expressed as ordinal severity categories. A generalized linear model for ordinal data was used to estimate the probability of response associated with exposure and severity category. Stratification of the regression model addresses systematic differences among studies by allowing one or more model parameters to vary across strata defined, for example, by species and sex. The ability to treat partial information addresses the difficulties in assigning consistent severity scores. Studies containing information on acute effects of tetrachloroethylene in rats, mice, and humans were analyzed. The mouse data were highly uncertain due to lack of data on effects of low concentrations and were excluded from the analysis. A model with species-specific concentration intercept terms for rat and human central nervous system data improved fit to the data compared with the base model (combined species). More complex models with strata defined by sex and species did not improve the fit. The stratified regression model allows human effect levels to be identified more confidently by basing the intercept on human data and the slope parameters on the combined data (on a C x T plot). This analysis provides an exposure-response function for acute exposures to tetrachloroethylene using categorical regression analysis.

Administration, Inhalation↗
PubMed1997

Adenovirus vector-infected cells can escape adenovirus antigen-specific cytotoxic T-lymphocyte killing in vivo.

The recent findings that prolonged expression of certain adenovirus (Ad) vector-encoded proteins, including human alpha1-antitrypsin (huAAT), mouse erythropoietin (EPO), and human factor IX, can be achieved in animals that do not mount an immune response to the reporter protein were obtained with mouse strains which have been shown to be capable of mounting a cellular immune response against Ad vector antigens. This suggests either that Ad vectors expressing nonimmunogenic transgenes fail to elicit a cellular immune response or that an Ad-specific cellular immune response does develop but is ineffective against cells expressing nonimmunogenic transgenes. Here we demonstrate that an Ad vector expressing huAAT administered by intravenous injection does stimulate an Ad-specific cellular immune response but that this response fails to abolish vector-directed gene expression in vivo. Moreover, expression of huAAT remained stable in animals stimulated by concurrent and multiple administrations of different Ad vectors or viruses. We also demonstrate prolonged expression of huAAT in CD1 mice transgenic for the huAAT gene, indicating that long-term expression is not restricted to C57BL/6 mice. These results demonstrate that under some circumstances, an Ad vector can direct prolonged expression of a nonimmunogenic transgene despite the presence of a robust Ad-specific cellular immune response.

Adenoviridae↗
PubMed1997

Ca(2+)-dependent p47phox translocation in hydroperoxide modulation of the alveolar macrophage respiratory burst.

Oxidative stress produces dual effects on the respiratory burst of rat alveolar macrophages. Preincubation with hydroperoxide concentrations [H2O2 or tert-butyl hydroperoxide (t-BOOH); < 50 microM] enhances stimulation of the respiratory burst, whereas higher concentrations inhibit stimulation. Both the enhancement and inhibition are markedly attenuated by buffering t-BOOH-induced changes in intracellular Ca2+ concentration ([Ca2+]i). Phosphorylation of the NADPH oxidase component p47phox and its translocation from cytoplasm to plasma membrane are essential in respiratory burst activation. Phorbol 12-myristate 13-acetate (PMA)-stimulated p47phox phosphorylation was negligibly affected by 25 or 100 microM t-BOOH. Nonetheless, 25 microM t-BOOH increased PMA-stimulated p47phox translocation, whereas 100 microM t-BOOH decreased PMA-stimulated translocation. In unstimulated cells, however, neither phosphorylation nor translocation of p47phox was affected by t-BOOH. Buffering of the t-BOOH-mediated changes of [Ca2+]i abolished the effects of t-BOOH on PMA-stimulated translocation in parallel to effects upon the respiratory burst. The results suggest that the dual effects of hydroperoxides are mediated, in part, by Ca(2+)-dependent processes affecting the assembly of the respiratory burst oxidase at steps that are separate from p47phox phosphorylation.

Animals↗
PubMed1997

A conserved cytoplasmic region of ROMK modulates pH sensitivity, conductance, and gating.

ROMK channels play a key role in overall K balance by controlling K secretion across the apical membrane of mammalian cortical collecting tubule. In contrast to the family of strong inward rectifiers (IRKs), ROMK channels are markedly sensitive to intracellular pH. Using Xenopus oocytes, we have confirmed this pH sensitivity at both the single-channel and whole cell level. Reduction of oocyte pH from 6.8 to 6.4 (using a permeant acetate buffer) reduced channel open probability from 0.76 +/- 0.02 to near zero (n = 8), without altering single-channel conductance. This was due to the appearance of a long-lived closed state at low internal pH. We have confirmed that a lysine residue (K61 on ROMK2; K80 on ROMK1), NH2 terminal to the first putative transmembrane segment (M1), is primarily responsible for conferring a steep pH sensitivity to ROMK (B. Fakler, J. Schultz, J. Yang, U. Schulte, U. Bråandle, H. P. Zenner, L. Y. Jan, and J. P. Ruppersberg. EMBO J. 15: 4093-4099, 1996). However, the apparent pKa of ROMK also depends on another residue in a highly conserved, mildly hydrophobic area: T51 on ROMK2 (T70 on ROMK1). Replacing this neutral threonine (T51) with a negatively charged glutamate shifted the apparent pKa for inward conductance from 6.5 +/- 0.01 (n = 8, wild type) to 7.0 +/- 0.02 (n = 5, T51E). On the other hand, replacing T51 with a positively charged lysine shifted the apparent pKa in the opposite direction, from 6.5 +/- 0.01 (n = 8, wild type) to 6.0 +/- 0.02 (n = 9, T51K). The opposite effects of the glutamate and lysine substitutions at position 51 (ROMK2) are consistent with a model in which T51 is physically close to K61 and alters either the local pH or the apparent pKa via an electrostatic mechanism. In addition to its effects on pH sensitivity, the mutation T51E also decreased single-channel conductance from 34.0 +/- 1.0 pS (n = 8, wild type) to 17.4 +/- 1 pS (n = 9, T51E), reversed the voltage gating of the channel, and significantly increased open-channel noise. These effects on single-channel currents suggest that the T51 residue, located in a mildly hydrophobic area of ROMK2, also interacts with the hydrophobic region of the permeation pathway.

Acetates↗
PubMed1997

Inhibition and restimulation by insulin of cellular autophagy in distal tubular cells of the kidney in early diabetic rats.

Cellular autophagy in the cells of distal tubular segments (DT cells) of the kidney cortex in streptozotocin-diabetic rats was evaluated by quantitative electron microscopy. Five days after streptozotocin administration, volume and numerical densities of autophagic vacuoles (AVs) in DT cells were reduced by 56 and 57%, respectively. The correction of the diabetic state by insulin injection reversed the inhibition of cellular autophagy. Volume and numerical densities of AVs increased by 97 and 53%, respectively. Endogenous insulin replacement by islet transplantation showed the same effect on cellular autophagy. Volume and numerical densities of AVs increased by 82 and 34%, respectively, as compared with sham-operated diabetic animals. The data show that, during diabetic kidney hypertrophy, the cellular autophagy is inhibited in DT cells to the same extent as in proximal tubular cells, suggesting that DT cells contribute in a balanced manner to hypertrophic growth of the kidney cortex. Similarly, DT cells are involved in the catabolic reaction, i.e., stimulation of autophagy, after metabolic correction of the diabetic state by insulin.

Animals↗
PubMed1997

Antenatal betamethasone therapy augments isoproterenol and prostaglandin E2-mediated relaxation of preterm ovine pulmonary veins.

Antenatal glucocorticoid therapy improves pulmonary function in preterm newborns. We have determined the effect of antenatal glucocorticoid therapy on isoproterenol and prostaglandin (PG) E2-mediated relaxation in preterm ovine pulmonary veins after birth. Ovine fetuses (121 and 126 d of gestation; term = 150 d) received an ultrasound guided intramuscular injection of betamethasone, 0.5 mg/kg, or saline. Lambs were delivered 15 or 48 h later, ventilated for 3 h, and killed. Isolated fourth generation pulmonary veins were suspended in organ chambers filled with modified Krebs-Ringer solution (95% O2, 5% CO2) at 37 degrees C, and their isometric tension was recorded. During contractions to U46619, isoproterenol and PGE2 induced greater relaxations of pulmonary veins of betamethasone-treated lambs than those of control. Forskolin, an activator of adenylate cyclase, caused greater relaxation in veins of betamethasone-treated lambs than in those of controls. A greater relaxation of veins treated with betamethasone than that of control veins also occurred in the presence of isobutylmethylxanthine, an inhibitor of phosphodiesterases. All vessels relaxed similarly to 8-bromo-cAMP, a cell membrane-permeable analog of cAMP. When stimulated with isoproterenol, PGE2, and forskolin, adenylate cyclase activity of crude membrane preparations of pulmonary veins treated with betamethasone was greater than that of controls. These results demonstrate that antenatal betamethasone therapy potentiates isoproterenol and PGE2-mediated relaxation of pulmonary veins of preterm lambs; an enhanced adenylate cyclase activity explain in part the effect of antenatal glucocorticoid therapy on pulmonary veins of preterm lambs.

Adenylyl Cyclases↗
PubMed1997

Mammalian two-hybrid system: a complementary approach to the yeast two-hybrid system.

Here we demonstrate the use of a mammalian two-hybrid system to study protein-protein interactions. Like the yeast two-hybrid system, this is a genetic, in vivo assay based on the reconstitution of the function of a transcriptional activator. In this system, one protein of interest is expressed as a fusion to the Gal4 DNA-binding domain and another protein is expressed as a fusion to the activation domain of the VP16 protein of the herpes simplex virus. The vectors that express these fusion proteins are cotransfected with a reporter chloramphenicol acetyltransferase (CAT) vector into a mammalian cell line. The reporter plasmid contains a cat gene under the control of five consensus Gal4 binding sites. If the two fusion proteins interact, there will be a significant increase in expression of the cat reporter gene. Previously, it was reported that mouse p53 antitumor protein and simian virus 40 large T antigen interact in a yeast two-hybrid system. Using a mammalian two-hybrid system, we were able to independently confirm this interaction. The mammalian two-hybrid system can be used as a complementary approach to verify protein-protein interactions detected by a yeast two-hybrid system screening. In addition, the mammalian two-hybrid system has two main advantages: (i) Assay results can be obtained within 48 h of transfection, and (ii) protein interactions in mammalian cells may better mimic actual in vivo interactions.

Antigens, Polyomavirus Transforming↗
PubMed1997

[Study of the mechanism of regression of left ventricular hypertrophy in hypertension treated with slow-release verapamil].

Thirty-three hypertensive patients with left ventricular hypertrophy were treated with slow-release verapamil for 1 year. The left ventricula mass index (LVMI) and the concentration of intracellular calcium ion ([Ca2+]i) of lymphocytes were studied respectively at the beginning, the third, the sixth and the twelveth month of treatment. The results revealed that: 1 the LVMI was positively correlated with [Ca2+]i and mean arterial pressure (MAP); 2 the LVMI, [Ca2+]i and MAP were significantly decreased, after treatment; 3 the degree of reduction of LVMI (delta LVMI) was positively correlated with the degree of lowering of [Ca2+]i (delta [Ca2+]i) and MAP (delta MAP); 4 the LVMI and [Ca2+]i showed no significant change at the third month but significant decrease at the sixth and twelveth month of treatment. It suggests that besides the decrease of MAP the decrease of [Ca2+]i is a significant factor for mechanism of regression of LVH.

Adult↗
PubMed1997

[Prevention and treatment of stroke after hypertension for ten years in Hunan Province].

In this single blind, randomized multiple center clinical trial, the patients care period was divided into two stages. In the first stage (1985, 1-1989, 12), 984 cases were observed for 5 years whereas in the second stage (1990, 1-1994, 12), 2080 cases were observed and were subdivided into two groups, treat group and control, both were followed up for 5 years. The results showed that the prevalence of hypertension increased gradually. In the second stage, the average of blood pressure of the treatment group, using nitrendipine, was lower than that of the control group. There was significant difference between the two groups (P < 0.05). In the treatment group, the stroke and death rates were also decreased significantly as compared with the control group and the first stage group (P < 0.01).

Antihypertensive Agents↗
PubMed1997

[Distribution of fibronectin in kidney of IgA nephropathy and its clinicopathological correlation].

To understand of fibronectin (Fn) distribution in kidney of IgA nephropathy (IgAN) and their meaning, we studied 107 cases of IgAN. Strong positive staining of Fn was shown in mesangial areas with proliferation, crescents, segmental sclerosis, and sclerosing glomeruli. 33 patients (group M) had Fn distributed only in mesangium, and 74 (group B) had Fn along the capillary walls as well as mesangium. Compared with those in group M, patients in group B showed more severe renal histological lesions (P < 0.01), crescent formation and stronger staining of IgG, C3 (P < 0.05) and IgA (P < 0.01) along the capillary walls. More severe changes of GBM were found in group B under electron microscopy. Clinically, 24th protein excretion (P < 0.01), incidences of hypertension and nonselective proteinuria were significantly higher (0.01 < P < 0.05), and Ccr was lower (0.01 < P < 0.05) in group B. 44 patients were followed up for 19.2 months, and the incidence of renal function deterioration in group B increased much more (0.01 < P < 0.05) than that in group M. Our results dmonstrated that the increase of Fn along the golmerular capillary walls might reflect that excessive proliferation of mesangial matrix, severe immune injury in capillary wall and damage of GBM, which are correlated with unfavorable clinical features and progression of the disease.

Adult↗
PubMed1997

[Predictive value of IL-2R in renal tissue during acute renal allograft rejection].

The pattern of intragraft immunological events associated with acute cellular rejection (ACR) has been previously defined. We conducted a retrospective longitudinal study to compare the clinical significance of various immunological markers in renal materials obtained from human renal allografts. Three to 6 consecutive allograft biopsies were obtained from 17 serial human transplant recipients over an 8-month period. A total of 59 core needle biopsies were examined. The expression of interlukin-2 receptor (IL-2R) in interstitial infiltrates, as well as the presence of CD4/CD8 T cell infiltrates were assessed by immunocytochemical staining of frozen sections. When ACR occurred, IL-2R expression increased about 16.3 fold in the renal specimens significantly as compared with those specimens without ACR. After MTX-pulse therapy the expression of IL-2R in biopsies were evidently down-regulated about 60%. The results suggested that the expression of IL-2R in renal allograft may be a useful and helpful adjunct in the diagnosis of ongoing acute cellular rejection, and decrease in these expression may be indicative of successful antirejection therapy.

Adult↗